ATP Oil & Gas announces first production success of Garden Banks 409

HOUSTON, Sept. 25, 2001 -- ATP Oil & Gas Corporation (Nasdaq: ATPG) announced first production from its two successful deepwater wells in its Garden Banks Block 409 Field, known as "Ladybug." The gross production level for Ladybug is estimated at 8,000 barrels of oil per day and 6 MMcf of natural gas per day, or approximately 3,100 Bopd and 2.5 MMcf per day net to the company's interest. ATP commenced production from the Garden Banks Block 409 Field by utilizing two six-inch eighteen-mile flowlines. Ladybug is the company's first deepwater subsea development project (approximately 1,360 feet of water depth). ATP and Unocal Corp. (NYSE: UCL) each hold a 50% working interest, with ATP as operator. ATP is one of the most active operators utilizing subsea technology in the Gulf of Mexico.

With the inception of production from Ladybug, ATP has increased its net production to approximately 90 MMcfe per day and expects record production in 2001. ATP has already surpassed its stated goal of increasing proved reserves in 2001 by more than 200% of current year projected production. After nine years of activity, on December 31, 2000 ATP had 125 Bcfe of proved reserves; in 2001 after eight months, on August 31, ATP recorded 210 Bcfe of proved reserves.

"We are pleased to have proven our capabilities in deepwater with our Ladybug project and we are delighted with the continued expansion of our business plan to acquire, develop and produce in deeper waters," said T. Paul Bulmahn, ATP's Chairman and President.

About ATP Oil & Gas Corporation

Houston-based ATP Oil & Gas is one of the fastest growing energy companies focused on acquisition, development and production of natural gas in the Gulf of Mexico and the North Sea. The company was recently added to the Russell 2000(R). Inc. magazine listed ATP on the Inc. 500 as the 5th fastest growing private company in 2000, up from its ranking of 21st in 1999, and the fastest growing energy company for both years. The company now trades publicly as ATPG on the NASDAQ National Market.

Forward-looking Statements

Certain statements included in this news release are "forward-looking statements" under the Private Securities Litigation Reform Act of 1995. ATP cautions that assumptions, expectations, projections, intentions or beliefs about future events may and often do vary from actual results and the differences can be material. Some of the key factors which could cause actual results to vary from those ATP expects include changes in natural gas and oil prices, the timing of planned capital expenditures and availability of acquisitions, uncertainties in estimating proved reserves and forecasting production results, operational factors affecting the commencement or maintenance of producing wells, the condition of the capital markets generally, and uncertainties regarding environmental regulations or litigation and other legal or regulatory developments affecting our business. More information about the risks and uncertainties relating to ATP's forward-looking statements are found in our SEC filings.